1. Field of the Invention
The present invention relates to a light controlling apparatus and an optical apparatus.
2. Description of the Related Art
In an ultra-small image pickup mechanism used in a cellular phone and an endoscope, an optical system having a simple structure without an aperture control function has been used. With increase in number of pixels of a small image pickup element in recent years, a demand for an ultra-small aperture control mechanism for having a high image quality has been increasing. As an example of an optical diaphragm apparatus which can be used in such ultra-small image pickup apparatus, an aperture control mechanism disclosed in Japanese Patent Application Laid-open Publication No. 2005-128450 will be described by using FIG. 7.
Diaphragm blades 1 and 2 are pivoted to a base plate 20. At one end of the diaphragm blades 1 and 2, one end of a first shape memory alloy 3 is engaged, and is put around a clip 7. A bias is applied on the pair of diaphragm blades 1 and 2 in a direction of closing, by springs 4a and 4b. One end of a second shape memory alloy 5 is fixed to the clip 7, and one end of a spring 6 is engaged with the clip 7, thereby applying the bias on the clip in a downward direction. The shape memory alloy 3 is self-heated by an SMA drive circuit 12, and moves the diaphragm blades 1 and 2. When there is a substantial change in an environment, the apparatus is protected by the second shape memory alloy 5, and a stabilized control independent of a temperature change, is carried out.
In a small image pickup apparatus having a high resolution, generally, a light controlling apparatus such as an aperture controlling mechanism is disposed between a plurality of lenses. In a conventional aperture controlling mechanism, it is necessary to draw a wire for supplying an electric power from the aperture mechanism to a shape memory alloy. However, normally, a gap between the two lenses is extremely small, and it is quite difficult to draw a wire through the gap. Moreover, the necessity of wire has been an obstacle in a size reduction. Furthermore, when it is desirable to be accommodated in a case in which an image pickup optical system is sealed, such as in an endoscope, it is substantially difficult to draw a wire from a sealed case